To have access to all the RealTime Optimization Pack 2.2 features, you must upgrade your Skype for Business 2.x to the June, 2016 PU (15.0.4833.1001) or subsequent PU or your RealTime Optimization Pack 1.x to this version.
If you are upgrading from 1.x to 2.1, you must upgrade both RealTime Connector and RealTime Media Engine to retain optimized operation.
If you are running the 32-bit Citrix Receiver for Linux and 32-bit RealTime Media Engine on 64-bit systems, you can use the 32-bit RealTime Media Engine package to upgrade.
If you want a 64-bit RealTime Media Engine, first uninstall both 32-bit Citrix Receiver for Linux and 32-bit RealTime Media Engine, and then install the 64-bit Citrix Receiver for Linux, version 13.2 or later and 64-bit RealTime Media Engine
During 2015, Citrix and Microsoft co-developed a new architecture for delivering Skype for Business in virtualized environments. This new architecture provides smooth upgrades from one 2.x release to the next by allowing customers to upgrade the HDX RealTime Connector on the XenApp and XenDesktop servers before upgrading the RealTime Media Engine on all user devices. But upgrading from the original 1.x architecture to 2.x is more challenging because 1.x versions of the RealTime Media Engine are not compatible with the new RealTime Connector 2.x . Therefore, during the interval between upgrading the RealTime Connector and upgrading the RealTime Media Engine on user devices, optimized delivery of the Skype for Business client is not possible.
For the smoothest possible upgrade, we recommend using Electronic Software Delivery mechanisms to update the RealTime Connector and the RealTime Media Engine on user devices as close to simultaneously as possible. To manage server load if some users need to use Skype for Business audio-video services while a major version mismatch still exists between the RealTime Connector and the RealTime Media Engine, the HDX RealTime Connector provides fallback controls (introduced in the 2.1 release). These controls enable administrators to configure whether to totally deny audio-video service until the RealTime Media Engine is upgraded to 2.x, permit only audio, or permit both audio and video. Server-side video processing has the greatest impact on CPU usage and server scalability.
The Lync 2013 client version 15.0.4859.1002 (released in September 2016) includes a fix to support co-residency of the Lync VDI Plug-in with this version of HDX RealTime Media Engine, facilitating migration. The migration procedure: